Safety controls for elevators



July l2, 1960 Filed Oct. 1l, 1957 SAFETY CONTROLS FOR ELEVATORS B. A. WITTKUHNS 2 Sheets-Sheet 1 15 f z w: I I I5 I I6 I/ i 2 1 I i 1o? lll- J5 FIG. 5

FIG. 1

INVENTOR BRUNO A WITTKUHNS BY @IWI m ATTORNEY July 12, 1960 B. A. wlrTKUHNs 2,944,635

SAFETY CONTROLS FOR ELEVATORS Filed Oct. 11, 1.957 2 sheets-sheet 2 FIG. 2

FIG. 4

INVENTOR BRUNO A.W|TTKUHNS BY Mmmm ATTORNEY United States `Patent nzfsmrtsas Y -sAnErr coNrRoLsroR ELuvA'rons;

Bruno A. wittkuhns, Skaneateles, NX., Yassignor to Hawkeye `Products.'Corporation, Syracuse, NX., a corporation of New York Filed ocr. 1:1, 1951, seLfNo. 689,602 voisins. (criar-ss) This invention relates v.broadly 4to elevator structures,

and lhas particular reference to safety controls Afor anY elevator of the type thatfcan-be moved from-one Alocation to another for interim use.

In the'elevator structure to whichlthe present invention relates, the elevator car is adapted to carry either passengers or materials, but unlike the so-called shaft type-elevators rthe structure can be -readily disassembled and freerected at another site. This mobilityror portability of the elevator structure renders it particularly -usefnl Yfor construction,v maintenance and lrepair operations on multistory building'islor ther-like, and thestructure can also be used vas a'permanent installation, Vif desired,

`The elevator car or cage, which Ais of'cantilever con- I' struction, fis raised and lowered b ya pair ofmotor actu- Y 'atedcables and is guided duringsuch movement'by la single -npstanding column which may -be of unitary or sectional form. A normally inoperative cam or pawl is mounted Aon, the car, and this pawllis engageablewi'ththe xed column to immediately stop -the downwardmove# ment o f the car should either or both/of thercables break, or if one cable should stretch abnormally, or the event that the speed of the car `exceeds Aa predetermined safe limit. 'In accordance with the invention, the safety pawl is arranged for actuation by either aA cable requalizer device or by a car mounted governor device,A as un'll be explained in detail below in connectionwithfthe -description of the annexed drawings.Y ,y f l, Y Accordingly, with heforegoing and other Yconsiderations rin View, 'it maybe stated -thatsthe 1broad objective of the `present ,invention is 'to provide Vnovel safety controls-for an elevator structure of the abovedes'eribed type. Another important object ofthe invention is to provide safety controls for an elevator structure of the above describedtype which are `completely reliable in operation and yet vare relatively simple in construction. Y

A frurther importantobject of thelinvention is to provide safety controlsA for an elevator Structureof the above describedr type .which respondlalmost instantaneously in the event of a'failurel andare positive 'in their car stoppins action. Y

A 2,944,635 Ratented `July l2; 11960 "ice Y i 4 Y 2 ranov'el cable attachment lmeans for Vthe elevator car in the-'formof arable V'equalizer device.

' Another .specific object .of the invention is tov provide a novel elevator safety control for an elevator car of ,cantilever constructionfwhich 'control isV operable by Ymeane of acar mounted governor device.

' lOther objects and advantages of the'invention will become apparent from `the `following detailed description therenfreadfin'conjunction with'the accompanying draw- .ingszwhich illustrate a representative embodiment of the invention'for the purpose of disclosure.

ln the drawings:

"Figure l is a fragmentary isometric view of a vportion 'of the 'elevator car and structural guide member `showing ,the'safety controls' embodying the invention, parts of the -struct'ureibeing broken away for greater clarity;

Figure^2 is an enlarged sidevelevationof a portion of a cable equalizer device'of the invention;

Figure 3 is an enlarged side elevationof the car safety pawl and yoperating linkagespconnected therewith;

' rFigure 4 is 'an enlarged top perspective view of a portion of-thecar mounted governorA and the operating linkage actuated thereby; and

Figure 5 is Ya-diagrammatic representation of the cantillever construction 'of lthe elevator car and the forces exerted by the car on the guide'column ,Y

Hav'ing reference now Vto, the drawings, wherein like.

' referencenumbers designate the ysan-1e parts in eachV of the -views,r`10 indicatesa'fragmentary portion ofthe elevator Scar platform, the, remainder of the car itself lbeing omittedfor greaterrclarity.k IMounted on one side of Athe car, and forming-apart thereof, are a pair of confronting lchannel or ACbeams'll which are spaced apart to provide yain/enclosurefor the'control mechanisms to be described.

'The-car is -guided as lit is raised andlowered by means of 'anH-'beamlL oneside 14 of Vwhich extends into the space between the Cbeams,.of-thecar where it is engaged 'on 'its vinner 'face and yedges by a .plurality of pairs of oppositely disposed guide rollers 15 secured to the C- 4beams- The (3v-beams and platform 10 of the car form a cantilever construction whereby the weight of the car exerts a ,moment resulting ,in forces .on the H-beam as 'represented by -the arrows .'16 of Figure 5. The H-beann preferably :provided in sections which may 'be bolted `or welded together to 'forma straight, rigid column or monorail extending up :to 250ft. or more in height. For la, moredeta'iled description of a bolted monorail and one methodV of vbracing same,v .reference may be had to SchuchertdPatent #2,531,346, assigned byV mesne assignmentsato theassignee of 'the Apresent application and invention, saidgpatent also disclosing a cantilever type Acar coristruction. ,Whilethe vH-beam ,columnfis ordinarily verticallvdisposed forivertical'V movement of ,the1car, `it

a sin ,further annimmt @uw of. theiiwemin, sito providesafety controls `for an elevatorfstructureof vthe Y above described typewhicli are located completely'within the-,cawrfage' 0f theelevator. 1 Y

@other important gsjenor the inversin' is to providerovel elevator safety'ctnrtrols which are operable Y other.

A still `further important object of ,the :invention is .to provide novel elevator safety control structure which fis strong and durable, and 'yet is Arelatively inexpensiverto manufacture.

' braided steel Y,cables .'17 4each vof which terminates ina thim'ble 18 secured Vto a cable ,equalizer device Amounted can' alsobe erected for inclined car movement by slightly modifying the carstructnre. Y

'Ilieleleyator car is .raised and lowered a Apair of onthe car. Cables 17- extend upwardly vfrom .the car and pass overa sheave .or pulley v(not shown) ,mounted at the top kof the jfl-beam .columnand then extend down- A.wardly onfthetopposite side Nof the I,column to la double grooved motor;H t. Y t Y l ,Y .In-accordance with .the invention, control `means are provided to immediately .stop the downward-movement drum? (not shown) operatedby a suitable-electric .of thetcar if .either cable 17 should stretch abnormally or A more specific object Yof the linvention is to `Vprovide break and to this end, .the 4car .is provided with a heavy, toothed cam or paw-1 20 which movable into engagementY with, the H-beam column :to hold the car at the point of engagement. The pawl 20 is'rockableonla stub shaft 21 supported at its ends in a pair of spaced, vertical plates 24 secured to the C-beams 11 as shown.

plates 22 extending between a pair of spaced, horizontal The outer, arcuate end of the pawl and the teeth 25 formed thereon are hardened so that when the pawl is rocked in the counter-clockwise direction the rst tooth will bite into the softer material of the H-beam column due to the downward motion of the car and will prevent further travel thereof, see Figures 1 and 3.

The pawl is normally held out of engagement with the H-beam column by 'a means to be presently described, and yin this normal position there is a clearance of approximately 1/s" between the column and upper toothed edge of the pawl. This clearance -is maintained by a spacing roller 27 which is mounted on the car and bears against the inner side 14 of the column' just above the pawl, the roller being supported on a shaft 28 and secured to one of the spaced, vertical plates 22. However, in case the clearance becomes greater than the minimum of IAS" due to Wear or a slight displacement, the second, third or fourth tooth on the pawl will engage the H-beam column rather than the first tooth.

The cable equalizer device above referred to comprises a pair of arm plates 30 which are pivotally mounted at their midpoints on -a block 31 secured to the upper end of a rod or plunger member 32. Pivotally supported between the outer ends of the arm plates 30 are a pair of apertured blocks 34 to which bolts 35 are -adjustably secured ias by nuts 36. The upper ends of and repair work can proceed without delay. The strueture described, however, goes beyond the case of damage to just one cable and also makes provision for stopping the car in the unlikely event that both cables should break simultaneously. In such instance, with neither cable exerting any upward force, the rod 32 will simply be moved downwardly under the action of compression spring 42 to actuate the pawl as `above described.

The pawl 20 is normally held out of engegement with the H-beam column by means of a linkage which includes a rod 51 pivotally secured at its upper end to the inner bifuracted end of the pawl. This rod extends downwardly from the pawl through -a notch 52 in the lower horizontal plate 24 and is pivotally connected at these bolts are threaded into yoke blocks 37 which are secured to the cable thimbles 18 by means of pins 38 as shown-in Figures l and 2. The structure just described is assembled so that in operation there is equal tension on the cables 17 and the arm plates 30 are held in a substantially horizontal position on blocks 31 by the cables.

The rod or plunger member 32 passes with a slidable tit through aligned bores in the horizontal plates 24, and intermediate these plates it passes through a slot or its lower end to a transversely extending lever 54. The lever 54 is rockably connected as lat 55 to one of the C- beams 11 and the free end thereof is provided with a pair of spaced pins 57 which form `a yoke structure on the lever. This yoke straddles a vertically disposed governor rod 58 which is guided for longitudinal sliding movement by aligned bores in a pair of horizontal bracket plates 60 secured to the right hand G-beam as is best shown in Figure l.

An open compression spring 62 is positioned on the governor rod 58 between the lower bracket plate 601 and the yoke pins 57 on lever 54. This spring holds the yoke up against a transverse pin 64 through the governor rod and, lat the same time, acts through the rod 51 to hold the pawl Ztl in its inoperative position as shown in Figure l. However, it will be apparent that when the pawl is positively rocked in the counter clockwise direction by the rod 32 of the cable equalizer device as previously described, the spring 62 will permit downward "t movement of the rod 51 and lever 54, the spring channel 40 formed in the inner end of the pawl 20. Just below the upper plate 24, the rod 32 is threaded and carries a nut 41 which limits the upward movement of the rod against the force of the cables `acting thereon. A spring 42 is positioned on the rod between the lower plate 24 `and a retaining -washer 44 held in position by a nut 45, the spring normally being held in a compressed state by the upward force of the cables. Between the plates 24, the rod is provided with a transversely extending pin 47 which contacts the upper edge of the pawl without pressure when the rod is held in its upper position by the cables as shown in Figure l.

Mounted on the car above the arm plates 39 is a bar 48 provided with a pair of spaced pins 50 on its lower edge, see Figure 2. If either one of the cables should stretch abnormally or break, as for example, the right hand cable in Figure 2, the other cable will rock the arm plates 30 on the block 31 until they contact one of the pins 5t? as shown. The pin contacted then acts as a fulcrum for the plates whereby the upward force of the undamaged `cable imparts a downward movement to the block 31 and rod 32 which movement is aided by the compression spring 42. As the rod 32 moves downwardly, the. pin 47y thereon rocks ,the pawl 20 into engagement with the H-beam column yand the rst tooth of the pawl is positively driven into the column by the downward movement of the car which is thereafter immediately stopped. The above described action thus occurs automatically in the event of `abnormal stretching or'breakage of either cable, and, in actual embodiments of the invention, a fully loaded car can be stopped within one quarter of an inch of travel after Vthe pawl has been actuated.

In connectionl with the above described action, it should berpointed out that the safety factor for the cables is such thateither cable alone will safely support a loaded car but the safety device is necessary nonetheless so that immediate notice of any damage will beY given simply being compressed by the yoke pins 57 during such movement.

The governor rod 58 form-s a part of a linkage between the pawl 20 and a oar mounted governor device which will also cause the pawl to beV actuated if the speed of the car exceeds a predetermined safe limit. To this end, the lower end of the rod is normally engaged by a latch plate 65 which is adapted to be tripped by the governor to permit actuation of the rod. The latch plate 65 is in the form of a bell crank, and one `arm 67 of the crank is positioned beneath a small roller 68 on the lower end of the rod to hold it in the position shown in Figure 1 against the downward bias of a compression spring 70 which is mounted on the rod between a collar 71 secured thereto Iand the lower bracket plate 61. 'I'he latch plate is pivotally mounted on an upstanding bearing pin 72, and the larm 67 thereof is urged into engagement with the rod by means of a coil spring 74.

The governor dev-ice of the invention comprises a pair of positively disposed rollers 75 (only one of which is visible in Figure yl) that `are respectively journalled in bosses 77 secured to the C-beams 11 of the elevator car. The rollers bear against theV inner side 14 of the H-beam column due to the cantilever construction of the car, see Figure 5, and 4are rotated by the motion of the oar relative Vto the column. Formed integrally with each roller is a gear 78 and these gea-rs mesh with pinions 80 carried on the opposite ends of a shaft 81 journalled in a pair of spaced upstanding plates 82. InV between the plates 82, a bevel gear 84 is loosely mounted on the shaft and the back side of this gear is engaged by a conventional friction disc clutch (not shown) secured to the shaft, .the clutch being provided to absorb any starting and -stopping shock of the car by allowing slippage between the shaft and the bevel gear.

Bevel gear 84 meshes with a bevel pinion 85 on the lower end of a shaft 87 depending `from `a governor disc 88, the disc shaft being supported by a bearing housing (not shown) mounted on horizontal plate secured to the plates 82. A pair of trip levers 91, Figures 1 and 4, are pivotally mounted Aon the governor disc 88 as `at 92,

Y and the -free ends of these levers are normallyretained within the circumferential boundary of the jdisc by means of tension springs 94 extending between posts 95,' 96 on the levers and disc respectively. l'he tension of springs 94 is factory adjusted so that'if t lie` elevator car 'asti-ieee llov/fer the and' alixed, upstanding structural member kto guide 'the 'car during its movement: a safety device to prevent downward' movementof the car in the event of 7 breakage or stretching of either `of said .cablescomprising to limit the movement of the trip levers `in either direction, the outer stops being located -so that the trip levers Ycan move out just 'far enough to trip the latch plate when the governor disc is rot-ated in the counterclockwise direction by the downward v:movement ofthe car.

YWhen the latch plate 65 is vtripped .by vthe governor and rotated in the clockwise direction, the arm-67 thereof moves out from Vbeneath the governor rod 5S which 'is immediately moved downwardly under the action of compression spring 70. When the governor rod moves .downwardly, the transverse pin 64 on the rod depressesthe lever 54 and rod 51 which rocks the pawl 20 into engagement with the H-beam column. This action occurs entirely independently of the cable equalizer device since the latter is not rigidly connected to the pawl and engages it only through the contact pin 57 on the plunger rod 32. It will thuskbe seen that either of the above described Vsafety controls is operable to actuatethe safety pawl iridependently of the other, and thatthis is ,accomplishedb'y the lost-motion connections ofthe linkages'fin theformv of the various spring andpin arrangements. f-It will also be apparent that, if for any reason the Vcable equalizer device should vfail to operate, the Egovernor device will immediate- .ly actuate the safety pawl in the -event that ,the cable damage results in excessive car speed. v 1

Since the rod 51 and lever 54 are ,actuated whenever either safety contrlis operated,fmeans areprovidedon the lever to stop theelectric Jmotorfor the cable drum when the pawl is moved'into engagement with the H-beam column, so vthat Ythe drum will notfcontinueztorfeed the cable after the car has been stopped. Tothis end, a micro switch 100 for the motor is'mounted on the C-beam above thehinged .endof the lever, .andthe ldownwardly'.projectling plunger 101 forthe-switch sengaged by a-smalldisc 102 onthe upper endtofan adjustable screw 104 passing through the lever. When `the .lever-is held in :its `upper .position as shown in Figure Vl-.bythe :spring 62,'fthe disc .1'02 depresses .the plunger so thatlthe v{motor-switchis closed. However, whenthe .leveris'roked downwardly by either the cable equalizer device or the governor device, the disc is moved away from the plunger which moves outwardly of the switch housing and opens the switch. 4

From the foregoing description it will be apparent that the present invention provides novel and very practical safety controls for an elevator structure of the type described. The controls are completely reliable in operation, and are immediate and positive in stopping all movement of the elevator car.V In addition, the controls are compactly arranged within the elevator car structure itself, and the relatively simple construction thereof permits easy assembly, inspection and maintenance.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiment disclosed is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims.

What is claimed is:

l. In an elevator structure including a cantilever type elevator car having a pair of cables operable to raise and a toothed safety pawl of hardened material pivotally mounted on said caradjacent said structural member, a rst spring means normally holding said pawl outof engagement with said structural member, a plunger member -mounted on said car for vertical movement between upper and lower limiting positions, means onsaid plunger memberV engaging said pawl, said last-named means being operable against the action of said first spring means to pivot said pawl into engagement with said structural member when said plunger is moved downwardly towards its lower position, a second spring means on said plunger member normally urging the memberV downwardly towards its Vlower position, a rockerY arm pivotally secured intermediate its ends to the upper end of said plunger member, each ,of said cables being secured at one end to the ends of said rocker arm, said cables normally holding the arm againstrocking movement on said plunger and yalso holding Y,said plunging member in its upper posi- .tion against Ithe action of said second spring means, said rocker arm being rocked on said plunger member' by either one of said cables upon the breaking or stretching of the .other cable, and fulcrumA means on said car engaged-by said rocker Varm when it rocks to cause said plunger member to vmove downwardly and pivot said safety pawl, said plunger member also being moved downwardly to actuate said pawl in the eventof simultaneousbreakage -of both cables `bysaid secondspring means.

2.` vElevator structure as `deiinedjin claiml including a -rnotor to-actuate vsaidpairofcables, a normally closed switch for saidfmotor ,on'said elevator car, and means 4o'perably connecting said safety pawl and switch to 4open .the latter when the pawl is actuated by said plunger frnember.'

3. Structure of the character described comprising an .elevator .car having a pair of cables operable to raise and .lower the car; Va fixed, opstanding structural member .Imember, ,said pawlV being rockable into engagement with Y Vsaid structural member to prevent downwardmovement of the car; lmeans to actuate said pawl upon the'breaking or unequal stretching of said cables; and means to actuate sa'id pawl independently vof the cables when said car ex- Vwithfsaid structural member, and-a cable Yattachment-element mounted on -sa'id plunger member, each of said `'cables being-attached at one of lits ends to said'attachment element and normally holding it and the plunger member against movement, said plunger member being actuated to operate'said safety pawl by the breakage or unequal stretching of said cables; said second-named means including roller elements Ymounted on said car in engagement with said fixed structural member, a governor mounted on said car driven by said roller elements as the carV moves relative to the structural member, linkage means connected to said safety pawl, said linkage means being movable to rock the pawl into engagement with said structural member, latch means on said car normally holding said linkage means against movement, and means on said governor operable to disengage said latch means from said linkage' means when said car exceeds a predetermined speed.

4. In an elevator structure including an elevator car having av pair of cables operable to raise and lower the car and a fixed, upstanding structural member to guide the car during movement; a plunger member mounted on said car for vertical movement between upper and lower limiting positions, spring means on said plungerV v.member normally urging it downwardly towards its lower position, a cable equalizer bar pivotally secured intermediate its ends to the upper end of said plunger member, each of said cables being secured at one of its ends to the ends of said equalizer bar, said cables normally holding said bar in a stationary horizontal position on said plunger member and also holding the member in its upper position against the action of said spring means, said equalizer bar being rocked on said plunger member by either one of said cables upon the breaking or stretching of the other cable, fulcrum means on said car engaged by said equalizer bar when it rocks to cause said plunger member to move downwardly towards its lower position, said plunger member also being moved downwardly in the event of simultaneous breakage or unequal stretching of both of said cables by said spring means, roller elements mounted on said car in engagement with said fixed structural member, a governor mounted on said car and driven by said roller elements as the car moves relative to the structural member, a second plunger member mounted on said car for vertical movement between upper and lower limiting positions, spring means on said second plunger member normally urging it downwardly towards its lower position, latch means on said car normally holding said second plunger member in its upper position against the action of said last-named spring means, means on said governor operable at a predetermined speed of the governor to disengage said latch means from said plunger member to permit downward movement thereof, a toothed safety pawl pivotally mounted on saidcar adjacent said fixed structural member, said pawl being rockable into engagement with said structural member to prevent downwardk movement of the car, and means normally holding said pawl out of engagement with said structural member, said rst yand second plunger members being operably connected to said pawl to move it into engagement with said structural member against the action of said last-named holding means when either of said plunger members is moved downwardly towards its lower position.

5. In an elevator structure including an elevator. car of cantilever construction, means to raise and lower said car, and a xed, upstanding structural member to guide said car during its movement: a safety device to stop the downward movement of said car in the event that the speed of the car exceeds a predetermined safe limit comprising a toothed safety pawl pivotally mounted on said car adjacent said structural member, said pawl being rockable into locking engagement with said structural member, spring means normally holdingsaid pawl out of engagement with said structural member, roller elements mounted on said car in pressure contact with said ixed structural member, a governor mounted on said car and driven by said roller elements as the car moves relative to the structural member, a governor rod mounted on said car for vertical movement between upper and lower limiting positions, spring means on said rod normally urging it downwardly towards its lower position, means operably connecting said rod and safety pawl to rock the latter into locking engagement with said structural member upon downward movement of the rod, latch means on said car normally holding said rod in its upper position against the action of said rod spring means, and means mounted on said governor operable at a predetermined speed of the car to disengage said latch means from said rod to permit downward movement thereof.

6. Structure as defined in claim 5 including an electric motor to actuate said elevator car raising and lowering means, and a switch for said motor mounted on said car, said switch normally being held in closed position by said governor rod and safety pawl connecting means and being released to its open position when the pawl is actuated by the downward movement of the rod.

7. In an elevator structure including an elevator car having a pair of cables operabley to raise and lower the car and an upstanding structural member to guide the car during movement; a safety device to prevent downward movement of the car in the event of breakage or stretching of either of said cables comprising a safety pawl pivotally mounted on said car adjacent said structural member, means normally holding said pawl out of engagement with said structural member, a plunger member operably connected to said pawl, a rocker element pivotally secured intermediate its ends to said plunger member, each of said cables beingsecured at one end to the ends of said rocker element and normally holding it against rocking movement on said plunger member, said rocker element being rockedon said plunger element by either one of said cables upon the breaking or stretching of the other cable, independent means on said car engaged by said rocker element when it rocks to cause the element and plunger member to move together and pivot said safety pawl into locking engagement with said structural member, a normally closed electric motor switchon said car, `and linkage means operably connecting said safety pawl and switch to openV the latter when the pawl is actuated by said plunger member.

References Cited in the tile of this patent UNITED STATES PATENTS 299,544 Hoffnagle July 3, 1884 478,169 ODonnell July 5, 1892 620,215 McLean Feb. 28, 1899 620,364' Roli Feb. 28, 1899 717,240 Menzies Dec, 30, 1902 1,604,613 Stoller Oct. 26, 1926 1,834,652 Schmid Dec. 1, 1931 

